"She loves to work," he says. "She's a very strong person. Everybody goes through setbacks in their lives. [But] every day, I see her getting happier and stronger."

One of her biggest victories this year? Regaining visitation with Preston, 3, and Jayden, 2, her sons with ex-husband Kevin Federline.

So while her musical comeback is important, Spears has made it clear that motherhood comes first, says Rudolph.

"Her kids and balancing her life with her kids is an incredible priority – the No. 1 priority in terms of how I operate with her," he says.

Spears's boys can be seen in the film, which follows the pop star over three months as she records her upcoming album Circus, wins big at September's MTV Video Music Awards, and speaks frankly about her problems – including her failed relationships with Federline and Justin Timberlake.

The idea for the candid documentary sprung up during a conversation Spears and Rudolph had over dinner several months ago.

"It evolved and became a question of, What will she do? What will she say? How will she say it?" he says. "How will people view her after what she's been through and after all that they've seen in the tabloids over the past year or two?"

Adds Rudolph: "This became sort of a great way for her to say what she needs to say on her terms."